项目结构调整

Others/gong-wpf-dragdrop/src/GongSolutions.WPF.DragDrop/Utilities/HitTestUtilities.cs

@@ -0,0 +1,135 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Controls.Primitives;
+
+namespace GongSolutions.Wpf.DragDrop.Utilities
+{
+    public static class HitTestUtilities
+    {
+        public static bool HitTest4Type<T>(object sender, Point elementPosition)
+            where T : UIElement
+        {
+            var uiElement = GetHitTestElement4Type<T>(sender, elementPosition);
+            return uiElement != null && uiElement.Visibility == Visibility.Visible;
+        }
+
+        private static T GetHitTestElement4Type<T>(object sender, Point elementPosition)
+            where T : UIElement
+        {
+            var visual = sender as Visual;
+            if (visual == null)
+            {
+                return null;
+            }
+            var hit = VisualTreeHelper.HitTest(visual, elementPosition);
+            if (hit == null)
+            {
+                return null;
+            }
+            var uiElement = hit.VisualHit.GetVisualAncestor<T>();
+            return uiElement;
+        }
+
+        public static bool HitTest4GridViewColumnHeader(object sender, Point elementPosition)
+        {
+            if (sender is ListView)
+            {
+                // no drag&drop for column header
+                var columnHeader = GetHitTestElement4Type<GridViewColumnHeader>(sender, elementPosition);
+                if (columnHeader != null && (columnHeader.Role == GridViewColumnHeaderRole.Floating || columnHeader.Visibility == Visibility.Visible))
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        public static bool HitTest4DataGridTypes(object sender, Point elementPosition)
+        {
+            if (sender is DataGrid)
+            {
+                // no drag&drop for column header
+                var columnHeader = GetHitTestElement4Type<DataGridColumnHeader>(sender, elementPosition);
+                if (columnHeader != null && columnHeader.Visibility == Visibility.Visible)
+                {
+                    return true;
+                }
+                // no drag&drop for row header
+                var rowHeader = GetHitTestElement4Type<DataGridRowHeader>(sender, elementPosition);
+                if (rowHeader != null && rowHeader.Visibility == Visibility.Visible)
+                {
+                    // no drag&drop for row header gripper
+                    var thumb = GetHitTestElement4Type<Thumb>(sender, elementPosition);
+                    if (thumb != null)
+                    {
+                        return true;
+                    }
+                }
+                // drag&drop only for data grid row
+                var dataRow = GetHitTestElement4Type<DataGridRow>(sender, elementPosition);
+                return dataRow == null || Equals(dataRow.DataContext, CollectionView.NewItemPlaceholder);
+            }
+            return false;
+        }
+
+        public static bool HitTest4DataGridTypesOnDragOver(object sender, Point elementPosition)
+        {
+            if (sender is DataGrid)
+            {
+                // no drag&drop on column header
+                var columnHeader = GetHitTestElement4Type<DataGridColumnHeader>(sender, elementPosition);
+                if (columnHeader != null && columnHeader.Visibility == Visibility.Visible)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// thx to @osicka from issue #84
+        /// 
+        /// e.g. original source is part of a popup (e.g. ComboBox drop down), the hit test needs to be done on the original source.
+        /// Because the popup is not attached to the visual tree of the sender.
+        /// This function test this by looping back from the original source to the sender and if it didn't end up at the sender stopped the drag.
+        /// </summary>
+        public static bool IsNotPartOfSender(object sender, MouseButtonEventArgs e)
+        {
+            var visual = e.OriginalSource as Visual;
+            if (visual == null)
+            {
+                return false;
+            }
+            var hit = VisualTreeHelper.HitTest(visual, e.GetPosition((IInputElement)visual));
+
+            if (hit == null)
+            {
+                return false;
+            }
+            else
+            {
+                var depObj = e.OriginalSource as DependencyObject;
+                if (depObj == null)
+                {
+                    return false;
+                }
+                if (depObj == sender)
+                {
+                    return false;
+                }
+
+                var item = VisualTreeHelper.GetParent(depObj.FindVisualTreeRoot());
+                //var item = VisualTreeHelper.GetParent(e.OriginalSource as DependencyObject);
+
+                while (item != null && item != sender)
+                {
+                    item = VisualTreeHelper.GetParent(item);
+                }
+                return item != sender;
+            }
+        }
+    }
+}